Landing gear leg structure



Nov. 20, 1962 T. B. DALTON 3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 1I VENTOR. THOMAS 6. ALTON ATTORNEYS Nov. 20, 1962 T. B. DALTON 3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 2INVENTOR.

THOMAS B. DALTON ATTORNEYS Nov. 20, 1962 T. B. DALTON 3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 3FIG. 5 I 64 56.6

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Fla 7 INVENTOR.

THOMAS 5. DALTON BY & I f g wgduzb ATTOQNEYS Nov. 20, 1962 T. B. DALTON3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 4JNVEN TOR. Tuomna B. DALTON ATTOQNEYS Nov. 20, 1962 T. B. DALTON3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 5I I /44 5b 84 4 O INVENTOR. I THOMAS 6. DALTON ATTORNEYS Nov. 20, 1962T. B. DALTON 3,064,944

LANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 6INVEN TOR. THGMAs be DALTON wwi /f ATTORNEYS Nov. 20, 1962 T. B. DALTONLANDING GEAR LEG STRUCTURE Original Filed July 1. 1960 7 Sheets-Sheet 7INVENTOR. THoMAs b. DALTON United States Patent 3,064,944 LANDING GEARLEG STRUCTURE Thomas B. Daiton, Muskegon, Mich, assignor to WestMichigan Steel Foundry Company, Muskegon, Mich, a corporation ofMichigan Original application July 1, 1960, Ser. No. 40,238. Di videdand this application Apr. 12, 1961, Ser. No.

7 Claims. (Cl. 254-86) This invention relates to a leg structure in thelegs of landing gear of the type used to support the forward end of asemi-trailer when it is uncoupled from a tractor.

This application is a division of my co-pending application Serial No.40,238 filed July 1, 1960, and entitled Landing Gear Leg Structure.

Conventionally, a landing gear leg comprises upper and lower tubular legmembers which telescope relative to each other for lengthening the legto a trailer supporting position and shortening it to a retractedposition. The leg members are actuated by a jackscrew and nut mechanismwith a shaft and gearing for operating the jackscrew being mounted in ahousing adjacent the top of the upper leg.

Heretofore, the gear housing has consisted of a relatively heavy castingwhich had to be machined at numerous places to provide surfaces suitablefor engaging other components of the leg assembly. Heretofore, thevarious means for securing the leg members against relative rotationhave not been completely satisfactory from the stand point either ofmanufacturing cost or freedom from failure in use.

The object of this invention is to provide a strong landing gear legstructure which is lighter in weight and less expensive of manufacturethan previous structures and which has improved means for securing theupper and lower leg members against relative rotation in use.

Generally the invention contemplates forming the jackscrew gear housingof a cup-shaped metal stamping which is pierced to provide the variousopenings required therein, the surfaces provided by the drawing orstamping and piercing, without being further machined, being engageddirectly against other components of the landing gear. The inner lowerleg member is indented to provide an external groove engaged by a splineon the upper leg member. The components are arranged to facilitate rapidconvenient assembly during manufacture by inserting an assembly of thelower leg member, jackscrew, and nut upwardly into the upper leg member.

in the drawings:

FIG. 1 is generally a front elevational view of a semitrailer landinggear having a leg structure according to the present invention.

FIG. 2 is a side elevational view of the landing gear with the groundengaging Wheels being shown in dotted lines in a retracted position.

FIG. 3 is an enlarged generally vertical sectional view of the landinggear leg.

FIG. 4 is an enlarged sectional view on line 4-4 in FIG. 3.

FIG. 5 is an elevational view of a stamping forming the gear housing atthe upper end of the leg, with a portion broken away to illustratestructure.

FIG. 6 is a plan view of the stamping.

FIG. 7 is an elevational view illustrating the stamping welded to thetop of the leg, a portion being broken away and portions being shown inphantom to illustrate structure.

FIG. 8 isa sectional view on line 8-8 of FIG. 7.

FIG. 9 is a perspective exploded view illustrating the 3,954,944Patented Nov. 20, 1962 "ice;

relation between the upper end of the leg and its mounting plate.

H6. 10 is an elevational view illustrating the upper leg member weldedto the mounting plate.

FIG. ll is a section on line 1111 of FIG. 10.

FIG. 12 is an enlarged sectional view on line 12-12 of PEG. 3 with thejackscrew omitted.

FIG. 13 is aperspective exploded view of the lower leg member and itsbottom plate.

FIG. 14 is a perspective exploded view of the lower leg member andjackscrew nut prior to their assembly.

FIG. 15 is an exploded perspective view illustrating the parts formingthe connection between the upper and lower leg members prior to assemblythereof.

Shown in the drawings is the forward end of a semitrailer 20 havingframe members 22 to which a landing gear 24 is secured. The landing gearlegs 26 and 28 are constructed in accordance with -this invention andare identical except for having right and left hand relation. Each leghas ground engaging means such as wheels 30 at its lower end. A lateralbrace 32 is provided between the legs and each leg has a rear supportingstrut 34 anchored at its upper end to frame 22. Each leg includes anupper tubular member 36 and a lower tubular member 38 which aretelescoped vertically by means of a jackscrew mechanism to be describedwhich is operated by a crank 39 through shafting 42. Upper leg member 36comprises a tube 49 having an upper end face 43 (FIG. 7) to which acup-shaped stamping 44 is secured by welding 46. Stamping 44 provides ahousing for bevel gears 48 and 50 (FIG. 3) through which a jackscrew 52is operated by rotation of shafting 42.

Stamping 44 has cylindrical side walls 52 which are pierced to provideopenings 54 into which bushings 56 are press fitted for receiving shaft42. Each bushing 56 has a flange 58 which engages a surface portion 60of the stamping immediately surrounding opening 54-. Stamping 44 has abottom portion 62 pierced to provide an opening 64 through which theupper end of jackscrew 52 passes. Immediately surrounding opening 64 isa radial surface 66 and a contiguous axial or vertical surface 68, thesesurfaces containing a bearing 70 providing a journal for the upper endof jackscrew 52. Stamping 44 has an external annular face 72 which seatsdirectly against end face 43 of tube 40 when the stamping is welded tothe end of the tube. Stamping surfaces 60, 62, 66, 68 and 72 are thedrawn metal surfaces provided during the stamping or drawing of cup 44.These surfaces are engaged against the other components of the legstructure without further machining. Similarly, the surfaces definingbushing openings 54 and jackscrew opening 64 are the surfaces providedby piercing of the metal of cup 44 without further machining.

After cup 44 has been Welded to tube 40 and bushings 56 press fittedinto openings 44, the resulting upper leg member 36 is assembled with amounting plate 74 (FIGS. 9 and 10). Plate 74 has an upper saddle 76 witha concave surface 78 which seats against the cylindrical eX- terior ofcup 44. The saddle has an opening 80 into which an exteriorly projectingportion of bushing 56 fits. Plate 74 has a second saddle 82 engaged bythe cylindrical exterior of tube 40. The cup and tube are welded to thesaddles as at 84 and 86 (FIG. 10). Mounting plate 74 has flange portionswith bolt holes 88 to facilitate bolting onto trailer frame 22.

Lower leg member 38 comprises a tube 90 having welded at its lower endas at 92 (FIG. 14) a cover plate 94 which carries a pair of bearings 96which receive an axle 98 on which ground engaging wheels 3% are mounted.Tube 94 has one or more longitudinal grooves 101 in its external surfaceand these grooves extend longitudinally a distance at least as great asthe extension and retracting stroke of the lower leg member in moving toand from its ground engaging and retracted positions. The grooves arepreferably formed by deforming the metal of the tube wall inwardly by arolling process. By this means the grooves can be given considerabledepth, for example a depth equal to the thickness of the tube wall asshown in FIG. 12. Where two grooves are used as in the illustration, thegrooves are preferably disposed diametrically opposite each other. Thisfacilitates roll forming of the grooves and also enables the grooves tobe positioned at the forward and rearward extremities of the legrelative to the longitudinal direction of the vehicle so that the metalforming the grooves also provide stiffening ribs which resist bending ordistortion of the lower legs when the vehicle is moved over a surface onits landing gear wheels 30.

A jackscrew nut 102 having internal threads 1134 for engagement withjackscrew 52 is secured within the upper end portion 106 of leg tube 90with an outward flange 108 on the nut engaging the upper end face 110 ofthe tube. In heavy duty gear, flange 108 has a diameter greater than theouter diameter of tube 90 for a purpose to be described. Nut 102 haslongitudinal recesses 112 which accommodate the elongate inwardindentations 114 formed in rolling grooves 101). The nut is securedwithin the tube by a number of shouldered pins 116 having heads 118 andshanks 119 having a clearance fit respectively through holes 120 in thethreaded portions of nut 102 and smaller holes 122 in the upper end oftube 90.

The lower end portion 124 of the upper leg tube is provided with anopening 126 for each groove 100 in the lower leg tube 90. A bearing andreinforcing sleeve 128 is interposed between lower leg portion 124 andlower leg tube 90 and this sleeve has a flange 130 adjacent its lowerend which engages the lower end face of tube portion 124. Sleeve 128 hasan opening 132 for each opening 126 in the upper leg tube. Openings 132are longitudinally aligned with openings 126 when sleeve flange 130engages the end of tube portion 124.

An insert 134 is fitted into each pair of aligned openings 126 and 132and has a spline projection 136 which projects inwardly of sleeve 128into slidable spline engagement with a groove 1110 in the lower legtube. The spline surfaces 138 of projection 136 and the complementaryside surfaces 140 of groove 100 (FIGS. 12, 13 and are disposed at obtuseangles to the intersecting tangents of lower leg tube 90 to minimize thetendency of the tube and insert to be cammed away from each other, andthis, taken with the depth of the groove, insures against disengagementof the spline insert from the groove.

A split collar 142 is provided around lower portion 124 of the upper legtube and this collar retains spline inserts 134 in place in theirrespective openings. Collar 142 has a pair of radial lugs 144 which havealigned openings 146 through which bolts 147 pass for threadedengagement with nuts 148 to clampingly contract the collar around theleg, sleeve, and insert assembly. Collar 142 has a rear boss 150 forengagement with rear landing gear strut 34 and has another boss 152apertured for bolted engagement with cross brace 32 as shown.

Collar 142 has adjacent its lower end an inwardly eX- tending annularflange 154 and a dirt and grease seal 156 is contained in wipingengagement around lower leg tube 90 between this flange and flange 130on sleeve 128. Seal 156 is made of a suitable sealing material such as anatural or synthetic rubber or other elastomeric material. Seal ring 156has a pair of inward projections 158 engageable complementally withinspline grooves 100 in the lower leg tube to maintain the continuity ofthe seal across the groove regions.

To assemble the leg, the upper leg member 36 is welded to its mountingplate 74 and lower leg 38 is welded to its bottom plate 94 in the mannerdescribed. Split collar 142, seal ring 156 and sleeve 128 are theninserted over the upper end of lower leg tube 90 in that order.Jackscrew nut 102 is then dropped into place in the top end of lower legtube and flange 1118 brought into engagement with the top end face ofthe tube. Tube indentations 114 engage within nut recesses 112 and holesand 122 in the nut and tube respectively are aligned. Pins 116 areinserted outwardly into nut openings 120 so that their shanks 119project into tube openings 122 and their shoulders engage the interiorsurface of the tube. This is easily done manually because of theclearance fit between the pins and openings. Jackscrew 52 is thenthreaded into the nut until a stop pin 160 (FIG. 3) press fitted into athrough opening 162 in its lower end 164 is brought into alignment witha hole 166 in lower leg tube 90. (FIGS. 13 and 14.) A punch (not shown)is then inserted through hole 166 and pin 16!) is driven partially outof hole 162 so that it projects radially outwardly of jackscrew 152 toprovide a stop for engaging nut 102. The jackscrew retains pins 116within openings 120 and 122.

The jackscrew is then turned all the way down to the FIG. 3 positionwherein threads 104 run out and stop the screw. A thrust bearing 170 isinserted over the upper end portion 172 of the jackscrew and seated on ashoulder 173 thereon. The upper end of leg tube 90 and sleeve 128 arethen inserted into lower end portion 124 of the upper leg tube andsleeve flange 130 is engaged against the bottom end of the upper tube.This aligns openings 126 and 132 in the upper tube and the sleeve.Inserts 134 are now inserted through the aligned openings with splineprojections 136 engaged within grooves 100 in the lower tube. Collar 142is now slipped upwardly around the exterior of the lower end of theupper tube until seal 156 engages sleeve flange 130. Clamping bolts 147are now passed through their openings 146 in lugs 144 and tightened tosecure lower leg portion 124, sleeve 128, inserts 136, and seal 156 inassembled relation.

Lower leg tube 90 is then slipped upwardly in the outer tube until theupper end 172 of the jackscrew passes through the bottom opening 64 ingear housing cup 44 and thrust bearing 170 engages against bottomsurface 62 of the cup. Bearing 70 and beveled gearing 48 and 50 togetherwith a portion of shafting 42 may then be installed. Gear housing 44 isthen covered by a plate 174 secured in place as by screws (not shown)threaded into suitable holes 175 (FIG. 6) in the housing.

This leg structure facilitates considerable savings in the cost ofmanufacture which are passed on to the ultimate consumer. In part, thesesavings are effected by eliminating the necessity for machiningoperations of eight diflerent surfaces in the gear housing head 44,these surfaces being two each at 54 and 60, and one each at 62, 66, 68and 72 as pointed out above. The savings are also facilitated in part bythe simple assembly procedure described. One feature adding tosimplicity of assembly is that lower end plate 94 with its bearingelements 96, nut 102, jackscrew 52 and thrust bearing 170 can all beassembled to lower leg tube 90 before the latter is inserted into outerleg tube 40. In this regard. it is to be noted that nut flange 108 has adiameter no greater than the inner diameter of the lower end portion 124of the outer tube.

The lower end 124 of tube 40 co-operates with sleeve 128 and collar 142to provide strong lateral support for the lower leg 38 in its downwardposition. Engagement of nut flange 108 with the interior of outer legtube 40 supplements this support, enabling the gear to be used undersevere conditions such as where the supported vehicle, which may be anarmy vehicle, is operated over relatively rough ground. Where thevehicle is to be operated only on relatively smooth surfaces or pavementas commercial vehicles usually are, the enlarged nut flange isunnecessary, tube end 124, sleeve 128, collar 142 and interengaged nut102 and jackscrew 52 providing sufficient lateral support.

In use, it may be assumed that landing gear legs 26 and 28 have beenassembled to semi-trailer 20 as illustrated in FIGS. 1 and 2. The legsare operated between their downward ground engaging position and theirupward retracted position merely by turning operating handle 39 whichrotates shafting 42 to drive jackscrew 52 through bevel gears 48 and 50.Inner tube 90 telescopes with respect to outer tube 40 in slidingengagement with the guiding and reinforcing sleeve 128 and splineprojections 136 on inserts 134, engage in grooves 100 on the lower tube.Collar 142 securely holds the inserts in place and the support of thecollar pins the angles and depth of the interengaging splines andgrooves makes it virtually impossible for the inner and outer tubes totwist rotationally relative to each other under any loads which thelanding gear is designed to operate. The spline grooves 100 in additionto acting as such serve to stiffen the lower leg tubes.

1 claim:

1. In a landing gear for semi-trailers and the like of the type havingupper-outer and lower-inner relatively telescoping tubular leg membersactuated by a jackscrew journaled on the upper member engaged with a nuton the lower member, improved leg structure wherein said lower legmember and said nut have diameters less than the inner diameter of saidupper-outer leg member so that in manufacture said lower leg member, nutand jackscrew as an assembly can be inserted upwardly through the lowerend of said upper-outer leg member, a sleeve interposed between thelower end portion of the outer leg member and the inner leg member, saidsleeve providing a bearing surface against which said inner leg memberslidably engages .and providing lateral reinforcement for said legmembers, said outer leg member and said sleeve having aligned openings,an insert in said openings having an inward spline projection, saidinner leg member having means defining a spline groove engaged by saidprojection to secure said leg members against relative rotation, and acollar clamped around said lower end portion of said outer leg member toretain said insert in place and provide further reinforcement for saidleg members in extended relation thereof.

2. The combination defined in claim 1 wherein the wall of said inner legmember is deformed inwardly to form said spline groove, said groovehaving a depth which is about at least as great as the thickness of saidwall.

3. The combination defined in claim 2 wherein said inner leg member hastwo of said spline grooves generally diametrically opposite each otherand two of said splined inserts engaged therewith, said splined insertsand said aligned openings in said leg members cooperating to positionsaid grooves at the forward and rearward regions of said leg structureso that they form reinforcing ribs against forces tending to bend saidlower leg member when the vehicle which said leg structure supports isin motion.

4. The combination defined in claim 1 wherein said nut has a flangewhich projects radially into sliding engagement with the interior of theouter tube to supplement the lateral strength of said leg structure.

5. The combination defined in claim 1 wherein said sleeve has an outwardflange which engages the lower end of said outer leg member when saidapertures in said outer leg member and sleeve are longitudinallyaligned.

6. The combination defined in claim 1 wherein said collar has an inwardflange, a seal contained by said flange in slidable sealing engagementagainst said inner leg member below said outer leg member, said sealhaving inwardly projecting portions complementally engaging within saidspline groove to provide a continuous seal across the grooved regions ofsaid inner leg member.

7. The combination defined in claim 5 wherein said collar has an inwardflange, a seal contained between said collar flange and sleeve flange inslidable sealing engagement against said inner leg members below saidouter leg member, said seal having inwardly projecting portionscomplementally engaging within said spline groove to provide acontinuous seal across the grooved regions of said inner leg member.

References Cited in the file of this patent UNITED STATES PATENTS

